water demand assessment for urban projects

7/30/2019 Water Demand Assessment For Urban Projects

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WATER DEMAND ASSESSMENT


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General

Water demand is normally classified as domestic water demand water demand. Domestic water demand covers use of water for bathing, cooking and flushing i.e. for domestic purposes. Nodemand covers the use of water mostly for public purposes such a

educational institutions, offices, commercial establishments, railwagardens, swimming pools, theatres and fire fighting etc.


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TABLE 8 : WATER SUPPLY FOR RESIDENCES

1) For communities with population up to

20 000 and without flushing systema) water supply through stand post 40 lpcd ( Min )

b) water supply through houseservice connection

70 to 100 lpcd

2) For communities with population20,000 to 100,000 together with fullflushing system

100 to 150 lpcd

3) For communities with populationabove 100 000 together with fullflushing system

150 to 200 lpcd

NOTE - The values of water supply given as 150 to 200 litres per head per daymay be reduced to 135 litres per head per day for houses for Lower IncomeGroups (LIG) and Economically Weaker Section of Society (EWS), dependingupon prevailing conditions.

Ref : Code of Basic Requirements for Water Supply, Drainage and SanitationI.S. 1172 : 1993


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TABLE 9 : DOMESTIC AND NON-DOMESTIC USE

RECOMMENDED PER CAPITA WATER SUPPLY LEVELS FOR DESIGNING SCHEMES

S.No. Classification of towns / cities Recommended MaximumWate r Supply Levels

(lpcd)

1. Towns provided with piped water supply but without sewerage system

70

2. Cities provided with piped water supplywhere sewerage system isexisting/ contemplated

135

3. Metropolitan and Mega cit ies providedwith piped water supply where seweragesystem is existing/ contemplated

150

Note :

(i) In urban area, where water is provided through public standposts, 40 lpcd should be considered;

(ii) Figures exclude Unaccounted for Water (UFW) which should be limited to15%

Ref : Manual on Water Supply & Treatment, CPHEEO May, 1999


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Water demand is necessarily assessed for 100%

resources, water is allocated to consumers and ththe demand. Since most of the water supply schewater demand in the long run, it is necessary to e basis.


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DOMESTIC WATER DEMAND SURVEY

Field Surveys for water demand assessment need to bwhere they are to be posed for loan assistance from finconsumption for a service area forms the basis for esti

The present water consumption is estimated by conducafter classifying the same as per housing categories. Itdemand satisfaction is assessed to be very good. The


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(a) Bungalows with attached gardens/lawns

(b) Bungalows without gardens / lawns

(c) Traditional houses

(d) Flats

(e) Chawls

(f) Slums


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Final selection of categories depends upon local conditions aWater supply projects for urban centres most of the times

suburbs/groups of villages etc. The housing categories accordingly for these areas. A thorough knowledge of theservice area is necessary to identify the housing categories to


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The number of houses of each category to be surveyed dependsaccuracy. In the past, as few as 50 houses of a category have yieestimates of water demand for the same. If possible, the numbelarger side. In a typical case, about 350 houses of a category hyielding excellent estimates of the water demand. In case of foperative society consisting of number of buildings housing severmay be selected if available. The houses have to have worki

otherwise the same can be replaced/installed. In the case of houssimilar category of houses/flats, a single meter for the whole socie


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A questionnaire is normally prepared and filled in by the investigatonumber of persons staying in the house during the survey and the amnormally drawn by the household from any alternate source such Consumer meter readings are taken initially and after a minimum

fortnight. This leads to the estimation of per capita per day consumptieach household. A typical format for such a questionnaire is given in

The above survey is repeated for other housing categories in the proje

Specific statistical techniques need be used in drawing meaningful cothe water consumption data generated in the above domestic conssurveys.


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ANNEXURE - A

SAMPLE QUESTIONNAIRE FOR DOMESTIC DEMAND ASSESSMENT

S.No. Item

1. Name of the Consumer :

2. Address / Ward No. :

3. Plot Size / Flat Size :

4. Meter number :

5. Housing Cate gory * : I II III IV V

6. Number of Storeys : 1 2 3 4 multi-storeyed

7. Number of rooms :

8. Number of persons residing :

9. Number of taps :

10. Meter working ? : Yes No

11. Water Supply arrangement

Direct to O.H. tank : Yes No

To Sump at G.L and

pumped to O.H. tank

:

Yes NoAny other (Describe arrangement) :

12. Additional source of water present ?(Describe Additional Source)

:

13. Water consumption from past recordof billing for one year, if available

: ________ x 1000 litresin _______ days


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14. Survey observations : Start Date _____________

Start reading _____________ End date _____________ End reading _____________

15. Water consumption from addit ionalsource if any (to be assessed)

: Total consumption ______________ litres

16. Level of sat isfaction of consumer (to be assessed)

: very satisfactory (100%) satisfactory

* Housing CategoryI - Bungalows with attached garden lawnII - Bungalows without garde n lawnIII - Traditional houseIV - FlatsV - Chawls

ConclusionAverage lpcd rate ________

Name & Signatureof Investigator

Date


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TAB LE 10 : TYPICAL FREQUENCY DISTRIBUTION FOR WATER CONSUMPTION DATA

Number of Houses

Class Interval Bungalows Bungalows Traditional FlatsLpcd With Gardens Without House

Gardens0-25 0 0 0 0

25-50 0 0 0 0

50-75 0 0 6 0

75-100 0 3 7 9

100-125 6 5 19 5

125-150 4 5 15 8

150-175 5 6 9 4

175-200 6 3 10 4

200-225 7 2 5 2

225-250 13 2 2 4

250-275 3 1 0 4

275-300 5 2 0 1

300-325 3 4 0 3325-350 3 2 0 0

350-375 3 3 0 0

375-400 0 0 0 0

fi 58 38 73 44

Mean - ModeJp = --------------------------

Standard deviation


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Arithmetic Mean =

(Fi Xi )

------------ Fi


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2

(Standard deviation) =2

Fi ( Xi X av)

--------------------- Fi


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TABLE 11 : STATISTICAL PARAMETERS FOR VARIOUSHOUSING CATEGORIES

Categories

Parameters BungalowsWith

Gardens

BungalowsWithoutGardens

TraditionalHouses

Flats

Mean (lpcd) 225.4 205.3 139.7 172.1

Median (lpcd) 226.9 175.0 127.4 150.0

Mode (lpcd) 235.4 157.3 119.8 93.3

Stand Deviation (lpcd) 71.4 87.3 44.2 71.0

Pearsons first coefficientof skewness, Jp -0.14 0.55 0.45 1.11

The distr ibutions are not symmetrical. Their skewness is measured by the magnitudeof the Pearsons first coefficient of skewness Jp. If Jp 1 then the distributions aremoderate ly skewed and the mean represents the distribution. In case Jp 1 theskewness is not moderate and median will be the representative value for thedistribution. It is there fore concluded that the consumption rates for bungalows withand without gardens and traditional houses can be taken to be the mean values of their

distributions, while the same for flats can be taken as the median value of thedistributions. Based on these conclusions, demand forecasts can be then prepared.


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Justification Of Housing Categories

Consumers are normally categorised presuming that the water consumphopefully differ from each other for these categories. The representativcategories as computed above may appear different from each other. It to know if the difference amongst representative values is statistically stheir classification under different categories. If not so, then some of thmerged together thus reducing the number of categories. This situation using the technique known as Analysis of Variance.


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TABLE 13 5% POINTS OF FISHERS F DISTRIBUTION


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TABLE 13 : 5% POINTS OF FISHERS F - DISTRIBUTION

D1D2

1 2 3 4 5 6 7 8

1 101.45 199.50 215.71 224.58 230.16 233.99 236.77 238.882 18.513 19.000 19.154 19.247 19.290 19.330 19.353 19.3713 10.126 3.3567 3.2039 3.0948 9.0123 2.9480 8.8808 8.84524 7.7086 6.9445 6.5914 6.5883 6.2500 6.1631 6.0942 6.0410

5 5.0079 5.7861 5.4095 5.1922 5.0503 4.9503 4.8750 4.81836 5.9874 5.1433 4.7571 4.5337 4.3874 4.2839 4.2055 4.14007 5.5914 4.7374 4.3468 4.1203 3.9715 3.8500 3.7870 3.72578 5.3177 4.4590 4.0062 3.8378 3.6875 3.5800 3.5005 3.43419 5.1174 4.2565 3.8026 3.6331 3.4817 3.3738 3.2927 3.2290

10 4.9045 4.1028 3.7083 3.4780 3.3238 3.2172 3.1355 3.071711 4.8443 3.9823 3.6874 3.3567 3.2039 3.0948 3.0123 2.948012 4.7472 3.8853 3.4903 3.2502 3.1059 2.9961 2.9134 2.848013 4.5672 3.8056 3.4105 3.1791 3.0254 2.9153 2.8321 2.705814 4.5001 3.7380 3.3439 3.1122 2.9582 2.8477 2.7542 2.0987

15 4.5431 3.0823 3.2874 3.0538 2.9012 2.7005 2.7000 2.540816 4.4940 3.6337 3.2389 3.0069 2.8524 2.7413 2.6572 2.591117 4.4513 3.5916 3.1908 2.9647 2.8100 2.0987 2.6143 2.548018 4.4139 3.5546 3.1699 2.9277 2.7720 2.6613 2.5707 2.510119 4.3808 3.5219 3.1274 2.8951 2.7401 2.6263 2.5435 2.4768

20 4.3513 3.4928 3.0084 2.8661 2.7100 2.5990 2.5140 2.447121 4.6248 3.4668 3.0725 2.8401 2.6848 2.5727 2.4870 2.420522 4.3009 3.4434 3.0491 2.6167 2.6613 2.5491 2.4638 2.396523 4.2793 3.4221 3.0280 2.7955 2.6400 2.5277 2.4422 2.374824 4.2597 3.4028 3.0088 2.7763 2.6207 2.5082 2.4220 2.3551

25 4.2417 3.3852 2.9912 2.7687 2.6030 2.4904 2.4047 2.837126 4.2252 3.3090 2.9751 2.7420 2.5868 2.4741 2.3883 2.320527 4.2100 3.3541 2.9504 2.7278 2.5719 2.4591 2.3732 2.305328 4.1950 3.3404 2.9467 2.7141 2.5581 2.4453 2.3593 2.291329 4.1830 3.3277 2.9340 2.7014 2.5454 2.4324 2.3489 2.2782

30 4.1709 3.3158 2.9223 2.0896 2.5338 2.4205 2.3343 2.266240 4.0846 3.2317 2.8337 2.0000 2.4495 2.3359 2.2490 2.180260 4.0012 3.1504 2.7581 2.5003 2.3689 2.2540 2.1665 2.0910

120 3.9201 3.0718 2.6802 2.4472 2.2900 2..1750 2.0867 2.0104 3.8415 2.9957 2.6049 2.3719 2.2141 2.0985 2.0098 1.9384


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Comparison Between Ledger Data And Survey Data

It is possible to statistically compare the observed water consumsurvey with ledger readings noted down by the water meter reaAuthority for similar season for a given category of consumers this, it is necessary to use a statistical technique to find out whetdifference between the means of the two distributions, namely tthe field survey and the mean of the recorded ledger readings av probability level of say 99%.


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TABLE 15 : AREA UNDER STANDARD NORM AL CURVE

Z .00 .01 .02 .03 .04 .05 .06 .07 .08 .09

0.0 .0000 .0040 .0080 .0120 .0160 .0199 .0239 .0279 .0319 .03590.1 .0398 .0438 .0478 .0517 .0557 .0596 .0636 .0675 .0714 .07530.2 .0793 .0832 .0871 .0910 .0948 .0987 .1026 .1064 .1003 .11410.3 .1179 .1217 .1255 .1293 .1331 .1368 .1406 .1443 .1480 .1517

0.4 .1154 .1591 .1628 .1664 .1700 .1736 .1772 .1808 .1844 .18790.5 .1915 .1950 .1985 .2019 .2054 .2088 .2123 .2157 .2190 .2224

0.6 .2257 .2291 .2324 .2357 .2389 .2422 .2454 .2486 .2517 .25490.7 .2580 .2611 .2642 .2673 .2704 .2734 .2764 .2794 .2823 .28520.8 .2881 .2910 .2959 .2967 .2995 .3023 .3051 .3078 .3106 .31330.9 .3159 .3186 .3212 .3238 .3264 .3289 .3315 .3340 ..3365 .33891.0 .3413 .3438 .3461 .3485 .3508 .3531 .3554 .3577 .3599 .3621

1.1 .3643 .3665 .3686 .3708 .3729 .3749 .3770 .3790 .3810 .38301.2 .3849 .3869 .3888 .3907 .3925 .3944 .3962 .3980 .3997 .40151.3 .4012 .4049 .4066 .4082 .4099 .4115 .4131 .4147 .4162 .4177

1.4 .4192 .4207 .4222 .4236 .4251 .4265 .4279 .4292 .4306 .43191.5 .4332 .4345 .4357 .4370 .4382 .4394 .4406 .4418 .4429 .4441

1.6 .4452 .4463 .4474 .4484 .4495 .4505 .4515 .4525 .4535 .45451.7 .4554 .4564 .4573 .4582 .4591 .4599 .4606 .4616 .4625 .46331.8 .4641 .4649 .4656 .4664 .4671 .4678 .4686 .4693 .4699 .47061.9 .4713 .4719 .4726 .4732 .4738 .4744 .4750 .4756 .4761 .47672.0 .4772 .4778 .4783 .4788 .4793 .4798 .4803 .4808 .4812 .4817

2.1 .4821 .4826 .4820 .4834 .4838 .4842 .4846 .4850 .4854 .48572.2 .4861 .4864 .4868 .4871 .4875 .4878 .4881 .4884 .4887 .48902.3 .4893 .4896 .4898 .4901 .4904 .4906 .4909 .4911 .4913 .4916

2.4 .4918 .4920 .4922 .4925 .4927 .4929 .4931 .4932 .4934 .49362.5 .4938 .4940 .4941 .4943 .4945 .4946 .4948 .4949 .4951 .4952

2.6 .4953 .4955 .4956 .4957 .4959 .4961 .4962 .4963 .4963 .49642.7 .4965 .4966 .4967 .4968 .4969 .4970 .4971 .4972 .4973 .49742.8 .4974 .4975 .4976 .4977 .4977 .4978 .4979 .4979 .4980 .49812.9 .4981 .4982 .4983 .4984 .4984 .4985 .4985 .4985 .4986 .49863.0 .4987 .4987 .4987 .4988 .4988 .4989 .4989 .4989 .4990 .4990

Area covered for z= 2.58 = 0.4951 x 2= 0.9902

Say 99%


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The difference between the observed andLedger consumption rates is statistically

significant.The ledger readings are significantly onlower side as compared to observed

readings of water consumption.


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Domestic Water Demand Projections

The per capita representative water consumption rates for various housing categories a

developed above can be used in consultation with population projections for estimatindomestic water demand for specific areas in the service area. Where specific areahave a mix of housing categories, a weighted average per capita water consumptiorate for all housing categories in the area can be worked out and used in the watedemand projections. For improvements in living conditions, the water demand may bincreased in future suitably (typical improvement could be 2.5 to 5% of domestidemand per decade). Seasonal variation could be accounted for if data are availableUrban centres, most of the times have surrounding rural areas which need to bconsidered in the service area. For surrounding villages, depending upon the livinstandards, the domestic water consumption would be a fraction of the urban rates anthe same has to be assessed.

Rates of 70 to 75 percent of that for urban rates have been adopted in typical cases fosurrounding rural areas. During future demand projections, it is prudent to consideabout 5% increase per decade in the water consumption due to improvement in livinconditions of people.


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SEASONAL VARIATIONS

WATER DEMAND IS HIGHER IN SUMMER ASCOMPARED TO WINTER.IN THIRUVANANTHAPURAM ,THIS VARIATIONWAS FOUND TO BE ABOUT 8 %


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NON-DOMESTIC WATER DEMAND

This can be assessed based on water consumption data for

on I.S. / CPHEEO guidelines. For major projects, some of the by field measurements or by circulating questionnaires to vasuch as hotels, hospitals or other bulk consumers. Guidelines Tables 16 and 17and the same from CPHEEO are given inTable 18. Typicalquestionnaires to collect data from major consumers are given


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TAB LE 16 : WATER REQUIREMENTS FOR BUILDINGS

OTHER THAN RESIDENCES

SlNo.

Type of Building Cons umptionPer Day, litres

(1) (2) (3)

i) Factories w here bath roo ms are req uired to be provided 45 per head

ii) Factories w here no bath roo ms are requiredto be provided

30 per head

iii) Hospital (includ ing laundr y) :a) Number of beds not

exceeding 100340 per head

b) Number of beds e xceeding 100 450 per head *

iv) Nurses homes a nd medica l quarters 135 per head

v) Hostels 135 per head

vi) Hotel 180 per head *

vii) Offices 45 per head

viii) Restaurants 70 per seat

ix) Cinemas, concert halls and theatres 15 per seat

x) Schools :a) Day schools 45 per head

b) Boarding schools 135 per head

Ref : Code of Basic Requirements for Water Supply Drainage And SanitationI.S. 1172 : 1993

* Remarks : In a typical sample survey following rates were observedHospitals (beds > 100) - 590 l/bed per da yMajor ho tels ( 3 star to 5 star) - 820 l/bed per dayGardens - 80 kl / HA per day

Swimming Pools - 5% of treatment p lant capacity


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TABLE 17 : WATER SUPPLY FOR TRANSPORTATION CENTRES

Nature of Station

Where BathingFacilities

are Providedlitres / capita

Where BathingFacilities

are notProvided

litres / capita

a) Railways, bus statio ns and sea ports

i) Intermediate stations (excludingmail and express stops) 45 25

ii) Junction stations and intermediate

Stations where mail or expressstoppage is provided 70 45

iii) Terminal stations 45 45

b) Airports

International and domestic airports 70 70

NOTES :

1) The number of perso ns shall be determined by average number of passengers handled by the stat ion da ily; due co nsidera tion may be given tothe staff and vendors likely to use fac ilities.

2) Consideration should be given for seaso nal avera ge peak req uirements.

Ref : Code of Bas ic Requirements for Wa ter Supply, Drainage and SanitationI.S. 1172 : 1993.


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TABLE 18 : INSTITUTIONAL NEEDS

Institutions Litres per head per day

Hospital (including laundry) (a) No. of beds exceeding 100 450 (per bed)

(b) No. of beds not exceeding 100 340 (per bed)

Hotels 180 (per bed)

Hostels 135

Nurses homes a n d medical quarters 135

Boarding schools / colleges 135

Restaurants 70 (per seat)

Air ports and sea ports 70

Junct ion S tations and intermediate stationswhere mail or express stoppage (bot h railwaysand bus stations) is provided

70

Terminal stations 45

Intermediate s tations (excluding mailand express stops)

45(could be reduced to 25 where bathing fac ilities are not provided

Day schools / colleges 45

Offices 45

Factories 45(could be reduced to 30 where no bathingrooms are required to be pro vided).

Cinema, concert halls and theatres 15

Re f : Manual on Water Supply & Treatment CPHEEO May, 1999


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ANNEXURE - B

SAMPLE QUESTIONNAIRE FOR HOTEL WATER DEMAND ASSESSMENT

1. Name of the Hotel :

2. Address :

3. Category : Star

4. Plot Area : Sq.m.

5. Rooms Beds :Future planning

At prese nt 2005 2010 2015rooms beds

6. If tubewell has been installed(a) No. of tubewells(b) Total qua ntity of

water being drawn

daily litres day

:

7. Air conditioning pla nt(a) Total Capac ity :(b) Running hours :(c) Consumption of water :

8. Swimming Pool treatme nt Plant Capac ity :

9. Water req uirement for swimming pool per day

:

10. Water consumption for Restaurants CoffeeShop

:

11. Water consumption of laundry water day :

12. Consumption water for gardening day :

13. Estimated Total Consumption of water day

:

14. Consumption assessed per year from pastwater bills

:

15. Any other deta ils :

Date Name & Signat ure of Investigator


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ANNEXURE - C

SAMPLE QUESTIONNAIRE FOR HOSPITAL WATER DEMAND ASSESSMENT

1. Name of the Hospital :

2. Address :

3. Plot Area : Sq.m.

:

Future planning

At prese nt 2005 2010 2015

4. Number of beds :

5. Total No. of staff :

6. Residential flats quarters(a) No. of flats quarters :(b) No. of persons resid ing :

7. Air conditioning plant :(a) Total capacity :(b) Running hours day :(c) Cons umption of water day :

8. Water Coo lers in Offices(a) Number :

9. If tubewe ll has been insta lled(a) No. of tubewells :(b) Total qua ntity of water being drawn

daily :

10. Capacity of underground ta nk :

11. Capacity of overhead tank :

12. Requirement of water for laundry day :

13. Is canteen facility available ? if yes, water consumption requirement for ca nteen day

14. Any other details :

Name & S ignature of Investigator

Date


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FIRE DEMAND

0.5

Q = 100 (P)Q is in KL/ DAY,P is the population in Thousands


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Fire Demand is Occasional

Used mostly in Designing LocalDistribution Networks


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TYPICAL WATER DEMANDSFOR

INDIAN CITIES


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Domestic Demand lpcd

HOUSING Thiruvananthapuram Kochi Kozhicode

Large Bunglows 225 250 225

Small Bunglows , 200 200 200Flats, TraditionalHouses

Small Houses 140 145 140


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Domestic Demand lpcd, Ahmedabad

Housing

Flats and Bunglows 260

Chawls 140

Huts 75


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Domestic Demand, lpcd, Mumbai

Area Housing

City Flats, Bungalows 295

A, D wardsFlats, Bunglows 250B, C, E wards

Suburbs Flats,Bunfglows 250Chawls 182slums 90


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Domestic Demand, lpcd, Delhi

Housing

Private plotted 360Private FlatsCantonmentGovt. Housing 230

Traditional HousingResettled colonies/ villages 140


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Non Domestic Demand, Hyderabad

Hotels, 3 star to 5 star 820 l/ bed/day

Hospitals, 100 beds 520 l/bed/day And more

Gardens 80 kl/HA/day


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Non Domestic demand

Restaurents

Kochi 70 l /seat/ day as per survey

Kozhicode 70 l /seat/ day as per ledger


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GROSS WATER DEMAND

Gross water demand for the project service area can be computed by addidomestic and non-domestic water demand assessed using the above techniques considering the losses in the water treatment plants, transmission mains and thdistribution networks. Present leakage losses in the local distribution networksof the Indian Cities are very high. In a few typical cases 40% losses havreported. In major metro cities, leakage monitoring operations and repairs to leakages are in the on-going stage and future water demand projections should creduced leakages as a consequence of the above activities. In any case it woalmost impossible to have financially viable projects if the future leakages controlled by above measures. A typical future target could be 15% losses in tdistribution network which could be considered in projecting the gross water though, at times, the financial institutions might prefer 10%.


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THANK YOU

water demand assessment for urban projects

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